using Lucene.Net.Documents;
using Lucene.Net.Randomized.Generators;
using Lucene.Net.TestFramework;
using System.Collections.Generic;

#if TESTFRAMEWORK_MSTEST
using Test = Microsoft.VisualStudio.TestTools.UnitTesting.TestMethodAttribute;
#elif TESTFRAMEWORK_NUNIT
using Test = NUnit.Framework.TestAttribute;
#elif TESTFRAMEWORK_XUNIT
using Test = Lucene.Net.TestFramework.SkippableFactAttribute;
#endif

using Assert = Lucene.Net.TestFramework.Assert;

namespace Lucene.Net.Index
{
    using Directory = Lucene.Net.Store.Directory;
    using Document = Documents.Document;

    /*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
    * Unless required by applicable law or agreed to in writing, software
    * distributed under the License is distributed on an "AS IS" BASIS,
    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    * See the License for the specific language governing permissions and
    * limitations under the License.
    */

    using MockAnalyzer = Lucene.Net.Analysis.MockAnalyzer;
    using NumericDocValuesField = NumericDocValuesField;
    using PackedInt32s = Lucene.Net.Util.Packed.PackedInt32s;
    using RAMDirectory = Lucene.Net.Store.RAMDirectory;
    using TestUtil = Lucene.Net.Util.TestUtil;

    /// <summary>
    /// Extends <see cref="BaseDocValuesFormatTestCase"/> to add compression checks. </summary>
    public abstract class BaseCompressingDocValuesFormatTestCase : BaseDocValuesFormatTestCase
#if TESTFRAMEWORK_XUNIT
        , Xunit.IClassFixture<BeforeAfterClass>
    {
        public BaseCompressingDocValuesFormatTestCase(BeforeAfterClass beforeAfter)
            : base(beforeAfter)
        {
        }
#else
    {
#endif
        internal static long DirSize(Directory d)
        {
            long size = 0;
            foreach (string file in d.ListAll())
            {
                size += d.FileLength(file);
            }
            return size;
        }

        [Test]
        public virtual void TestUniqueValuesCompression()
        {
            IndexWriterConfig iwc = new IndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random));
            using (Directory dir = new RAMDirectory())
            using (IndexWriter iwriter = new IndexWriter(dir, iwc))
            {

                int uniqueValueCount = TestUtil.NextInt32(Random, 1, 256);
                IList<long> values = new List<long>();

                Document doc = new Document();
                NumericDocValuesField dvf = new NumericDocValuesField("dv", 0);
                doc.Add(dvf);
                for (int i = 0; i < 300; ++i)
                {
                    long value;
                    if (values.Count < uniqueValueCount)
                    {
                        value = Random.NextInt64();
                        values.Add(value);
                    }
                    else
                    {
                        value = RandomPicks.RandomFrom(Random, values);
                    }
                    dvf.SetInt64Value(value);
                    iwriter.AddDocument(doc);
                }
                iwriter.ForceMerge(1);
                long size1 = DirSize(dir);
                for (int i = 0; i < 20; ++i)
                {
                    dvf.SetInt64Value(RandomPicks.RandomFrom(Random, values));
                    iwriter.AddDocument(doc);
                }
                iwriter.ForceMerge(1);
                long size2 = DirSize(dir);
                // make sure the new longs did not cost 8 bytes each
                Assert.IsTrue(size2 < size1 + 8 * 20);
            }
        }

        [Test]
        public virtual void TestDateCompression()
        {
            IndexWriterConfig iwc = new IndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random));
            using (Directory dir = new RAMDirectory())
            using (IndexWriter iwriter = new IndexWriter(dir, iwc))
            {

                const long @base = 13; // prime
                long day = 1000L * 60 * 60 * 24;

                Document doc = new Document();
                NumericDocValuesField dvf = new NumericDocValuesField("dv", 0);
                doc.Add(dvf);
                for (int i = 0; i < 300; ++i)
                {
                    dvf.SetInt64Value(@base + Random.Next(1000) * day);
                    iwriter.AddDocument(doc);
                }
                iwriter.ForceMerge(1);
                long size1 = DirSize(dir);
                for (int i = 0; i < 50; ++i)
                {
                    dvf.SetInt64Value(@base + Random.Next(1000) * day);
                    iwriter.AddDocument(doc);
                }
                iwriter.ForceMerge(1);
                long size2 = DirSize(dir);
                // make sure the new longs costed less than if they had only been packed
                Assert.IsTrue(size2 < size1 + (PackedInt32s.BitsRequired(day) * 50) / 8);
            }
        }

        [Test]
        public virtual void TestSingleBigValueCompression()
        {
            IndexWriterConfig iwc = new IndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random));
            using (Directory dir = new RAMDirectory())
            using (IndexWriter iwriter = new IndexWriter(dir, iwc))
            {

                Document doc = new Document();
                NumericDocValuesField dvf = new NumericDocValuesField("dv", 0);
                doc.Add(dvf);
                for (int i = 0; i < 20000; ++i)
                {
                    dvf.SetInt64Value(i & 1023);
                    iwriter.AddDocument(doc);
                }
                iwriter.ForceMerge(1);
                long size1 = DirSize(dir);
                dvf.SetInt64Value(long.MaxValue);
                iwriter.AddDocument(doc);
                iwriter.ForceMerge(1);
                long size2 = DirSize(dir);
                // make sure the new value did not grow the bpv for every other value
                Assert.IsTrue(size2 < size1 + (20000 * (63 - 10)) / 8);
            }
        }
    }
}